Aircraft propeller



Nv. 29, 1932. w. F. wARFEL i AIRCRAFT PROPELLE Filed Sept. 22, 1930ATTORNEY Patented Nov. 29, 1932 WILLIAM F. WARFEL, OF WENDLING, REGONAmonAr'r rnoPELER Application filed September 22, 1930. Serial No.483,651.

My present invention has reference to an improved propeller which isprimarily desgned for use in connection with aerial navigation but whichmay be also employed for water navigation, and my object is an im-vproved construction of propellers in which provision made for obtainingabetter grip on the fluid medium through which the vehicle isbeinggpropelled.

Another and important object is the provision of a propeller havingfront and rear blades which extend radially from the hub indiametrically opposed directions, the said pairs of blades beingslightly offset With respect to each other, both sets of blades beingslightly rounded from their connection with the h'ub to their tips andtheir said tips rounded inwardly, both pairs of blades having theirouterfaces convex and their inner faces concaved and the inner pair ofblades being reduced to their connection With the hub so that both setsof blades,'in the operation thereof will act against a tangible fluidsurface and also relieving the body of the craft of the force of fluidwhich is otherwise directed thereagainst.

To the attainment of the foregoing the invention consists in theimprovcment hereinafter described and definitely claimed.

In the drawing:

Figure l is a side elevation of a propeller in accordance with thisinvention.

Figure 2 is a front elevation thereof,

Figure 3-is a sectional view approximately on the line 3-3 of Figure 1.

The hub 1 on the propeller merges into a bullet-shaped outer end 2 andthe hub 1 is connected to the propeller shaft 3 for the aircraft orship.

There is integrally formed on thehub 1 a pair of oppositelv directedlaterally extending rear blades 2' and a pair of laterally extendingfront blades 3' The blades are suitably spaced from each other. Thefront blades 3' are of a less length than the rear blades 2' and theblades 2' and 3' are slightly offset from each other, although thelmajor portions of the width of the blades 3' is disposed over the blades2'. The outer blades 53 3' are substantially of an eq'ual widththroughout and are slightly curved from their juncture With the hub totheir ends and their said ends are slightly Curved inwardly as at 4. Theouter faces of the blades 3' are cross sectionally yrounded or areconvexed, while the 55 inner faces of the blades from their tips 4' totheir juncture with the hub 1 are dished .or concaved, as at 5. Theedges and tips of the blades 3 are sharpened or feathered.

The inner blades 2', at their juncture with the hub are for a suitabledistance reduced 'in width, as indicated in the drawing by the numeralA(i and from thence the said blades are gradually widened outwardly sothat the active portions of the blades are of a slightly greater widththan that of the blades 3'. The outer or active portions 7 of the blades3' are substantially spoon-shaped, that is, the outer faces thereof areconvexed, as at 8, and the inner faces thereof are concaved, as at 9,the concavities being extended from the outer ends or tips of the bladesto their juncture with the reduced connecting portions 6 thereof withthe hub 1. The parts 6 are round in cross section.

A propeller constructed in vaccordance with my invention reducesvibration as there is a steady running of the propeller. Each of theinner and outer pairs of blades act independently upon the fluidsurface, as the outer 30 blades have a tendency'to cut through the fluidand the inner vblades likewise cut through the fluid. The Cuttingaction, however, contacts with the tangible fluid surface. The reducedinner ends 6 of the blades 7 relieve air pressure next to the hub, whichis impossible with ordinary propeller constructions while the tips 4' ofthe outer propellers tend to force the fluid rearwardly therefromagainst the convex faces of the inner propellers.

As disclo'sed by the drawing the pairs of bla-des 2' and 3' arerespectively arranged at a slight angle with respect to each other, sothat the trailing edges of the said 'blades are spaced a greaterdistance from each other than are their leading edges. This afi'ords apocket for trapping the fluid in its passage between the blades whichcauses the said blades to act on a tangible fluid surface when thepropeller is in operation.

It is to be understood that the details herein described and illustratedare for the purpose of explaining the nature of my invention and are tobe interpreted as illustrative and not in a limiting Sense.

Having described the invention, I claim:

A propeller of the type described, comprising a hub having a pointednose, and having spaced pairs of extending front and `rear blades, andwhich pairs of front and rear blades are arranged at angles with respectto each other so that the trailing edges of the blades are spaced agreater distanoe away from each other` than are the leading edges of theblades, the front blades being of an equal width throughout and havingtheir trailing edges, adjacent to their outer ends,

. Curved toward their tips, and said tips being rounded and the innerfaces of the said outer blades being dished throughout the lengththereof, the inner blades being of a greater length than that of theouter blades, and having reduced cross sectionally rounded portions attheir juncture with the hub and from said rounded portions beingsubstantially spoon-shaped and the concaved inner faces of the saidinner blades terminating at the juncture of the rounded and spoon-shapedportioneI of said blades.

In testimony wheref I afix my signature WILLIAM F. WARFEL.

